A solar cell utilizing an organic metal perovskite crystal material (perovskite solar cell) can provide a high conversion efficiency. A large number of reports have recently been published on improvement on conversion efficiency of a solar cell utilizing a perovskite crystal material in a light absorbing layer (e.g., Non-Patent Document 1 and Patent Document 1). The organic metal used is a compound represented by a general formula R1NH3M1X3 or HC(NH2)2M1X3 (where R1 is an alkyl group, M1 is a divalent metal ion, and X is a halogen). Spectral sensitivity characteristics of the compound are known to vary depending on the halogen and/or the ratio of the halogen (e.g., Non-Patent Document 2).
A perovskite crystal material, such as CH3NH3PbX3 (X: halogen), can be used to form a thin-film at low cost using a solution application technique, such as spin coating. Thus, attention has been directed to a perovskite solar cell utilizing such a perovskite crystal material, as a low-cost and high-efficiency next generation solar cell. Furthermore, a perovskite solar cell has also been developed that incorporates, as a light absorbing material, CH3NH3SnX3 containing tin in place of lead (e.g., Non-Patent Document 3).